A conventional means for protecting a car from sunlight and rainwater is a car cover, which is made of canvas into a configuration similar to the car and has an elastic band provided a long a lower edge thereof, so as to enclose an entire car in the car cover. Another conventional means for protecting a car from sunlight is a collapsible sunshade that has a developed size similar to that of a windshield for mounting to an inner side of the windshield, so as to prevent sunlight from directly penetrating through the windshield into the car. While the conventional car cover is able to prevent sunlight from directly projecting on the car, it could not stop the heat from transmitting into the car. That is, the conventional car cover does not provide good thermal insulating effect. As to the conventional car sunshade, it does not block the sunlight from the car roof at all and is therefore useless in keeping the car at a low internal temperature.
Currently, people often drive cars to rural places for leisure activities, such as picnic and camping. The car is usually parked in an open-air place and becomes a center of the leisure activities. Therefore, it is desirable to have an easily operable and stably erected shade to effectively shield the car from sunlight and keep the interior of the car in a comfortable cool state. According to experiences, when the shade is supported over the car by a predetermined distance, the best sun blocking and thermal insulating effect can be obtained. Therefore, the developing of posts for easily and stably supporting a shade high above the car becomes an important issue.